In 1872, the Meiji government declared that February 11, 660 BC was the exact date on which the reign of Jimmu began. This was identified as the start of the Japanese nation. This mythical date was commemorated as the holiday Kigensetsu ("Era Day"). This national holiday was celebrated from 1872 to 1948.[10]

The Kigensetsu events in 1940 were special. They celebrated what was believed to be 2,600 years since the start of Emperor Jimmu's reign.[11]

There has been a similar Japanese national holiday since February 11, 1966. It is called National Foundation Day (Kenkoku Kinen no hi).[10]